/// <summary>
/// Obtain a smoothed path with the specified granularity from the current path using Catmull-Rom spline.
/// Also outputs a List of the points corresponding to the smoothed path.
/// </summary>
/// <remarks>
/// Implemented using a modified version of the code in the solution at
/// http://stackoverflow.com/questions/8702696/drawing-smooth-curves-methods-needed
/// </remarks>
public static InkStroke SmoothedPathWithGranularity(InkStroke currentPath, int granularity)
{
var currentPoints = currentPath.GetPoints().Select(inkPoint => inkPoint.Position).ToList();
NativePath smoothedPath;
List <NativePoint> smoothedPoints;
SmoothedPathWithGranularity(currentPoints, granularity, out smoothedPath, out smoothedPoints);
if (smoothedPath == null)
{
return(currentPath);
}
// create the new path with the old attributes
#if __ANDROID__ || __IOS__ || WINDOWS_PHONE_APP
return(new InkStroke(smoothedPath, currentPath.GetPoints(), currentPath.Color, currentPath.Width, currentPath.Source, currentPath.Timestamp));
#elif WINDOWS_PHONE
var da = currentPath.DrawingAttributes;
smoothedPath.DrawingAttributes = new DrawingAttributes
{
Color = da.Color,
OutlineColor = da.OutlineColor,
Width = da.Width,
Height = da.Height,
};
return(smoothedPath);
#elif WINDOWS_UWP || WINDOWS_APP
var da = currentPath.DrawingAttributes;
var builder = new InkStrokeBuilder();
builder.SetDefaultDrawingAttributes(new InkDrawingAttributes
{
Color = da.Color,
Size = da.Size
});
return(builder.CreateStroke(smoothedPath));
#endif
}
/// <summary>
/// Obtain a smoothed path with the specified granularity from the current path using Catmull-Rom spline.
/// Also outputs a List of the points corresponding to the smoothed path.
/// </summary>
/// <remarks>
/// Implemented using a modified version of the code in the solution at
/// http://stackoverflow.com/questions/8702696/drawing-smooth-curves-methods-needed
/// </remarks>
public static InkStroke SmoothedPathWithGranularity(InkStroke currentPath, int granularity)
{
var currentPoints = currentPath.GetPoints().ToList();
// not enough points to smooth effectively, so return the original path and points.
if (currentPoints.Count < 4)
{
return(currentPath);
}
// create a new bezier path to hold the smoothed path.
var smoothedPath = new NativePath();
var smoothedPoints = new List <NativePoint> ();
// duplicate the first and last points as control points.
currentPoints.Insert(0, currentPoints[0]);
currentPoints.Add(currentPoints[currentPoints.Count - 1]);
// add the first point
smoothedPath.MoveTo(currentPoints[0].X, currentPoints[0].Y);
smoothedPoints.Add(currentPoints[0]);
for (var index = 1; index < currentPoints.Count - 2; index++)
{
var p0 = currentPoints[index - 1];
var p1 = currentPoints[index];
var p2 = currentPoints[index + 1];
var p3 = currentPoints[index + 2];
// add n points starting at p1 + dx/dy up until p2 using Catmull-Rom splines
for (var i = 1; i < granularity; i++)
{
var t = (float)i * (1f / (float)granularity);
var tt = t * t;
var ttt = tt * t;
// intermediate point
var mid = new NativePoint
{
X = 0.5f * (2f * p1.X + (p2.X - p0.X) * t +
(2f * p0.X - 5f * p1.X + 4f * p2.X - p3.X) * tt +
(3f * p1.X - p0.X - 3f * p2.X + p3.X) * ttt),
Y = 0.5f * (2 * p1.Y + (p2.Y - p0.Y) * t +
(2 * p0.Y - 5 * p1.Y + 4 * p2.Y - p3.Y) * tt +
(3 * p1.Y - p0.Y - 3 * p2.Y + p3.Y) * ttt)
};
smoothedPath.LineTo(mid.X, mid.Y);
smoothedPoints.Add(mid);
}
// add p2
smoothedPath.LineTo(p2.X, p2.Y);
smoothedPoints.Add(p2);
}
// add the last point
var last = currentPoints[currentPoints.Count - 1];
smoothedPath.LineTo(last.X, last.Y);
smoothedPoints.Add(last);
// create the new path with the old attributes
#if __ANDROID__ || __IOS__
return(new InkStroke(smoothedPath, smoothedPoints.ToList(), currentPath.Color, currentPath.Width));
#elif WINDOWS_PHONE
var da = currentPath.DrawingAttributes;
smoothedPath.DrawingAttributes = new DrawingAttributes
{
Color = da.Color,
OutlineColor = da.OutlineColor,
Width = da.Width,
Height = da.Height,
};
return(smoothedPath);
#elif WINDOWS_UWP
var da = currentPath.DrawingAttributes;
var builder = new InkStrokeBuilder();
builder.SetDefaultDrawingAttributes(new InkDrawingAttributes
{
Color = da.Color,
Size = da.Size
});
return(builder.CreateStroke(smoothedPath));
#endif
}
